A body or surface in which every cross-section passing through the centre is a circle or ellipse. The Moon's shape conforms closely to an ellipsoid with three unequal axes, the shortest being the rotation axis and the longest aligned towards the Earth. Strictly speaking, the Earth is also ellipsoidal in shape since the equator is slightly elliptical, although the difference between its longest and shortest axes is less than 1 km. See also Spheroid.
Subjects: Astronomy and Astrophysics.